This invention relates to a driving system to be mounted on a positioning system which is required to perform precise positioning. In another aspect, the invention is concerned with an exposure apparatus or a device manufacturing method, for accurately transferring a reticle pattern to a wafer.
As regards the positioning precision, currently a nanometer (nm) order is required. For example, if a low thermal expansion material (thermal expansion coefficient 1xc3x9710xe2x88x926) of a size of 100 mm deforms by 100 nm in response to a temperature change of 1xc2x0 C. and even if a change in temperature of air in the light path of an optical interference type distance gauge is 1xc2x0 C., a measured value of position may change by 100 nm, depending on conditions. It is, therefore, necessary to use a cooling mechanism for collecting heat as radiated from a driving system, to prevent a temperature change.
Heat generation of a driving system produces thermal deformation of a structure or fluctuation of air, causing an error factor for the optical interference type distance gauge. In consideration of this, a precise positioning system uses cooling means based on a cooling medium, a heat pipe or a Peltier element. The temperature or flow rate of the cooling medium, the temperature at the heat radiating portion of the heat pipe or the driving current to the Peltier element is controlled, so that a driving system or a system having such a driving system is maintained at a predetermined temperature against heat generation from the driving system. Particularly, as regards adjustment of the cooling capacity of a cooling system, temperature measuring means may be provided in the vicinity of a heat generation source and, on the basis of the temperature as measured, the cooling medium temperature or the flow rate of the medium may be adjusted to perform cooling for the whole driving system (Japanese Laid-Open Patent Application, Laid-Open No. 302124/1995 and Laid-Open No. 302747/1995).
FIG. 8 shows an example of such a driving system. As shown in the drawing, this driving system operates to perform precise positioning of an object 110, to be positioned, by use of position measuring means 112, a controller 114 and a driver 115. There is cooling means with components 106a, 106b and 106c, for circulating cooling media 103a, 103b and 103c, to collect heat generated by the driving means 101a. The temperature or flow rate of the cooling medium is adjusted on the basis of the temperature of the subject to be cooled, as measured by a temperature sensor 105 and temperature measuring means 102, so that the driving system as a whole can be kept uniformly at a predetermined temperature.
In this example, however, the driving system needs the use of the temperature sensor 105 and the temperature measuring means 102, and the structure is complicated. It causes the following inconveniences.
(1) The assembling procedure is complicated.
(2) The cost of the driving system as a whole increases.
(3) Since the temperature sensor is provided within a casing in which the cooling medium flows, structurally, it is not easy to meet any disorder of the sensor.
These inconveniences then lead to a problem of reliability or high cost.
Further, with the feedback control using a sensor, there is a time lag from heat generation to cooling, to a predetermined temperature. It is, therefore, insufficient to reduce the thermal influence to the driving system, to the structure around the driving system, or to the environment, for example.
It is an object of the present invention to provide an exposure apparatus of higher reliability and reduced cost, in which, with respect to the cooling of the apparatus, simplification of structure and reduction of cost are accomplished and also the cooling effect is significantly improved.
It is another object of the present invention to provide a device manufacturing method using such an exposure apparatus.
It is a further object of the present invention to provide a stage system or a driving system to be used in such an exposure apparatus.
In accordance with an aspect of the present invention, there is provided an exposure apparatus for transferring a pattern of an original to a substrate, comprising: a control device for controlling an exposure operation of said exposure apparatus; and a temperature adjusting mechanism for controlling temperature, wherein said temperature adjusting mechanism is controlled on the basis of a signal produced by said control device for the exposure operation.
In one preferred form of this aspect of the present invention, one of thermal amount and cooling amount to be required is predicted on the basis of the signal, and said temperature adjusting mechanism is controlled on the basis of it.
Said temperature adjusting mechanism may include a cooling mechanism for controlling at least one of a flow rate of a cooling medium and temperature of the cooling medium.
There may be a plurality of temperature adjusting mechanisms, each corresponding to said temperature adjusting mechanism, for controlling temperatures of plural subjects to be controlled, wherein said temperature adjusting mechanisms may be controlled on the basis of a signal produced by said control device in relation to the subjects, for the exposure operation.
Said control device may include a drive controlling system for controlling a driving mechanism for performing drive of a stage, wherein, on the basis of a signal applied from said drive controlling system to said driving mechanism, a temperature adjusting mechanism for controlling a temperature of said driving mechanism may be controlled.
Said exposure apparatus may further comprise a drive controlling system for controlling a driving mechanism for performing drive of a stage, wherein, on the basis of a signal applied from said control device to said driving mechanism, a temperature adjusting mechanism for controlling a temperature of said driving mechanism may be controlled.
Said control device may include an exposure amount controlling system for controlling an exposure amount of an illumination optical system, wherein said temperature adjusting mechanism may be controlled on the basis of a signal produced by said exposure amount controlling system.
Said exposure apparatus may further comprise an exposure amount controlling system for controlling an exposure amount of an illumination optical system, wherein said temperature adjusting mechanism may be controlled on the basis of a signal applied from said control device to said exposure amount controlling system.
Said temperature adjusting mechanism may include means for adjusting temperature of one of the substrate and a holding member for holding the substrate.
Said temperature adjusting mechanism may include means for adjusting temperature inside said exposure apparatus.
Said temperature adjusting mechanism may be controlled on the basis of a signal produced by said control device for the exposure operation and a signal produced by a temperature measuring sensor.
In accordance with another aspect of the present invention, there is provided a device manufacturing method, comprising the steps of: producing, with a control device, a signal for an exposure operation; controlling a temperature adjusting mechanism for controlling temperature, on the basis of the signal; and transferring a pattern formed on an original to a substrate.
In one preferred form of this aspect of the present invention, the method further comprises predicting one of thermal amount and cooling amount to be required, on the basis of the signal.
The method may further comprise applying a resist to a wafer before an exposure operation, and developing the wafer after the exposure operation.
In accordance with a further aspect of the present invention, there is provided a driving system, comprising: a driving mechanism for producing a driving force; a drive controlling device for controlling said driving mechanism; and a temperature adjusting mechanism collecting heat from said driving mechanism, wherein a cooling amount of said temperature adjusting mechanism is controlled on the basis of a signal applied from said drive controlling device to said driving mechanism.
In one preferred form of this aspect of the present invention, said temperature adjusting mechanism is controlled on the basis of prediction of one of a cooling amount to be required for said driving mechanism and a thermal amount to be produced by said driving mechanism.
Said temperature adjusting mechanism may control at least one of a flow rate of a cooling medium and temperature of the cooling medium.
Said driving mechanism may include a linear motor.
Said linear motor may comprise a multi-phase type linear motor having plural coils, wherein said temperature adjusting mechanism may be operable to control temperatures of said coils, respectively, and wherein a cooling amount in relation to each coil may be controlled on the basis of a signal applied to the coil or a driver for energizing the coil.
Said temperature adjusting mechanism may be controlled on the basis of a signal produced by said control device for the exposure operation and a signal produced by a temperature measuring sensor.
In accordance with a yet further aspect of the present invention, there is provided a stage system, comprising: a movable stage; a driving mechanism for producing a driving force for said movable stage; a drive controlling device for controlling said driving mechanism; and a temperature adjusting mechanism collecting heat from said driving mechanism, wherein a cooling amount of said temperature adjusting mechanism is controlled on the basis of a signal applied from said drive controlling device to said driving mechanism.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.